package com.test.yest;
/**
 *
 **/

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 * @Author weiwei
 * @Date 2022-08-13 14:25
 * @description
 **/
public class C extends A{

    public static void main(String[] args) {
        List<? extends A> a = Collections.singletonList(new C());
        //a.add(new C());
        A a2 = a.get(0);
        List<? super A> a1 = new ArrayList<>();
        a1.add(new C());
        //C c = a1.get(0);
        C object = (C)a1.get(0);
    }
}
